The Professor teaches at Mars University and has worked for Momcorp on several occasions, but spends most of his time inventing ridiculous devices and sending the Planet Express delivery crew on suicide missions. While at Momcorp, he fell in love with the CEO, Mom, only to leave her and Momcorp when she decided to weaponize his "Q.T. McWhiskers" toy. What he is a professor of is never explicitly stated. In the episode Mars University when asked what he is teaching, he responds: "The same thing I teach every semester, the mathematics of quantum neutrino fields. I made up the title so no student would dare take it"; however, this declaration has not precluded the professor from demonstrating mastery of whatever field of science is convenient for a given episode's plot, as shown in Bender's Big Score when the professor proclaimed "I can wire anything directly into anything! I am the Professor!" Approximately 100 years ago he taught a young (not yet Professor) Wernstrom, whom Farnsworth regarded as a prized student. After he returned a pop quiz to Wernstrom with a grade of A-minus (for poor penmanship), the two became bitter rivals (established in "A Big Piece of Garbage").

As Philip J. Fry I's great (x30) nephew, it is likely that he is the great (x29) grandson of Yancy Fry, Philip J. Fry's brother from the 20th century. This would also make him the great (x28) grandson of Philip J. Fry II, Yancy's son (named after the series' protagonist, to carry on his memory), although his exact shared family members with Fry have not been stated. However, since Fry was revealed to be his own grandfather (established in Roswell that Ends Well and confirmed in The Why of Fry) he is also Fry's direct descendant, specifically his great (x31) grandson. He was originally going to be the (x29) grandson of Fry I's sister and Eddie Farnsworth but they were later taken out and were only mentioned in a story board.

The Season 7 episode "Near-Death Wish" reveals that the Professor's parents, Ned and Velma, are still alive and living in a virtual-reality retirement home on the Near-Death Star. In addition, he has a younger brother named Floyd, who may still be alive; at the end of the episode, Bender mentions having seen a man with that name who claims to be related to the Professor.

Professor Farnsworth is characterized by the catch-phrase "Good news, everyone!", frequently followed by very bad news or the announcement of a suicide mission; he acknowledges this in The Beast with a Billion Backs. On the very few occasions he has actual good news, he opens with "Bad news, everyone!" After firing Fry in "Law & Oracle", he states that he only says these phrases to make Fry "feel better about his pointless job." Another is his exclamation, "Sweet zombieJesus!" He often says "Eh Wha?" when unaware of the situation, or when someone questions a statement he has just made. The Professor often makes mutually contradictory statements just moments apart; this happens especially often when briefing his employees, with the prevailing second statement canceling a much more reassuring first sentence. For example, in "The Sting", he tells the crew their mission is to collect "ordinary honey." When told that it doesn't sound so dangerous, the Professor responds angrily, "This is no ordinary honey!"

In early episodes, Farnsworth would often see the crew in peril, but do nothing as he was "already in his pajamas". This was an early attempt at a catchprase that was scrapped after a few episodes.

The Professor is one of the oldest human beings on Earth (excluding those who have been cryogenically frozen or are kept alive as heads in jars), a title that he acquired after the events of the episode "A Clone of My Own", in which it was revealed that upon turning 160 (which he claimed was his 150th birthday), all humans are collected by the Sunset Robot Squad and sent to live out the rest of their days in isolation aboard the gigantic Near-Death Star (a play on the Death Star). In this episode, the plaque on his space within the Near-Death Star gives his year of birth as 2841. He mentions to his crew that he is actually 160 years old, and has been lying to protect himself. In episode 8 of the first season, "A Big Piece of Garbage," Farnsworth states, "Perhaps 149 is just too old to be a scientist."

In "Teenage Mutant Leela's Hurdles" his age is stated to be 161, and after he swam in the Fountain of Aging, he reported that he was "Even older! Huzzah!" His clone Cubert Farnsworth takes control of Planet Express, claiming the Professor had himself declared legally dead for tax evasion reasons. The Professor denies this allegation, claiming "you take one nap in a ditch at the park and they start declaring you this and that!" In Bender's Game, he stated that he is 165 years old.

In the episode "The Prisoner of Benda", Professor Farnsworth mentions in a conversation with Amy that he is entering into his 18th decade, indicating that he is over 170 years old. This age suggests that the world of Futurama progresses in years with the real world.

The Professor rarely worries about the safety of the crew, viewing them as a means to an end, as evidenced in the first episode. After remarking that he was looking for a new crew for his intergalactic space ship, he was asked "What happened to your old crew?" His response was "Oh, those poor sons of... — but that's not important! What is important is that I need a new crew!" Farnsworth's employees later discover that their predecessors died while gathering not-ordinary honey from Space Bees ("The Sting"). The Professor issues his new crew the previous crew's career chips from a manila envelope labeled "Contents Of Space Wasp's Stomach" ("Space Pilot 3000").

It was revealed in "Mobius Dick" that a previous crew was ingested by a four-dimensional space whale in 2961, only returning to Earth when rescued by Leela in 3011. This appears to be the only crew the Professor showed some emotion towards, given his purchasing of a monument to honor the 50th year of their disappearance. It was also revealed that Dr. Zoidberg was a member of this crew and was the only one to have survived, having left in an escape pod as the rest of the crew was devoured by the space whale.

He frequently sends his crew on dangerous missions even when he has the foreknowledge that they will probably not make it back alive. His missions are typically those other delivery companies will not take, such as serving subpoenas to Mafia-controlled worlds or casual deliveries to virus-infested planets. Even the commercial that he had produced for his company makes several remarks to this effect, including "When other companies aren't crazy or foolhardy enough…" and "Our crew is replaceable, your package isn't."

In one episode when the crew and his ship are sent off to war, he immediately tries to hire another crew, going so far as to assign them similar character roles ('...and you'll be the foul mouthed, alcoholic robot'); he is clearly surprised to be interrupted by his old crew returning, exclaiming "Oh Nicolas Cage, you're alive! I mean, thank Nicolas Cage you're alive," before telling the would-be new crew to check back in a week. Even his familial relationship to Fry does not do much (if anything) to dampen the glee with which he assigns deadly delivery missions. When asked about the nature of his delivery "business", Farnsworth once clarified that he viewed his company more as "a source of cheap labor, like a family." He also frequently covets his employees' organs and blood; he once mentioned that he keeps Amy Wong around because they share a blood type. In another episode, he tries to get Hermes Conrad to kill himself in a way that would not damage his liver because "other people need it".

It is established in the episode "Mother's Day" that the Professor was once Mom's lover and employee. However, they could not maintain their relationship due to Mom's lust for power, prompting them to break up (this reportedly happened three times). When Mom takes control of all the world's robots to cause an uprising, her sons Walt, Larry, and Igner attempt to get the Professor to seduce Mom and retrieve the remote for the robots. They get back together briefly, but break up once more when Mom learns the Professor had been initially using her. It is revealed in Bender's Game that the Professor is the biological father of Mom's youngest son Igner — ironically (or not), the one that the Professor despises the most.

An unusual utilization of his body occurred in "The Prisoner of Benda", when he trades bodies with Amy. Amy then proceeds to trade bodies with Leela, causing Fry to himself trade bodies with Dr. Zoidberg. Leela used Farnsworth's body to prove that her relationship with Fry is partially physical. At dinner, Leela (in Farnsworth's Body) is disgusted by Fry (in Zoidberg's body), and vice versa. When Leela-Farnsworth tells Fry-Zoidberg to prove his love, Fry-Zoidberg passionately kisses Leela-Farnsworth. This eventually leads to Leela-Farnsworth having Intercourse with Fry-Zoidberg. This marks the first known time Fry physically slept with a male. Mentally, however, Leela was the one who slept with Fry-Zoidberg.

As shown in "Near-Death Wish," the Professor has harbored a long-standing resentment against his parents for trying to repress his scientific curiosity when he was young. His constant experiments got him into trouble on a number of occasions, so the family moved to a farm in order to protect him. He was later committed to a mental institution, from which was later released, and does not see his parents again until the Planet Express crew finds them on the Near-Death Star and brings them to Earth. From them, the Professor learns they stayed on the farm in order to prevent their second son, Floyd, from meeting the same fate. The three reconcile and part on good terms, with the older Farnsworths returning to the Near-Death Star.

It was also revealed in "The Tip of the Zoidberg" that the Professor was scratched by a Tritonian yeti during a trip to Triton and made an arrangement with Dr. Zoidberg that should he begin to develop symptoms of hyper malaria, that Zoidberg would put him out of his misery. At the end of the episode, the Professor, upon seeing Zoidberg dejected about not having his coupon for a free tanning session, offers to pay for a session for the doctor.

The Professor claims to have created Planet Express to fund his experiments, though the company is frequently on the verge of bankruptcy. This is highlighted during "Future Stock," in which Hermes shows a pie chart of their income, the larger portion of it (approximately 65%) showing an $8 bank error in their favor; and in "Neutopia," in which the company faces foreclosure due to missed mortgage payments. In Futurama: The Game, which may not be considered canon, the Professor laments that the crew never remembers to charge anyone for the deliveries. The Professor is still capable of funding his experiments and paying for the inevitable repairs after the experiments go awry. The Professor states and/or implies in both "A Clone of My Own" and "Anthology of Interest I" that he has a vast fortune saved up.

Professor Farnsworth has pioneered many important inventions throughout the series, including the design of all modern robots and the meta-particles capable of converting dark matter into useful energy. Farnsworth has also received many honors. For stopping global warming and Richard Nixon's evil plans ("Crimes of the Hot"), Nixon awarded him the Polluting Medal of Pollution. He also received the Academy of Inventors award for stopping a giant trash meteor from destroying New New York City ("A Big Piece of Garbage"). He also invented the first robot capable of qualifying for a boat loan ("A Clone of My Own") and the Planet Express Ship's dark matter engines. His "Smell-O-Scope", which detects scents throughout the universe, has been used in many important situations. In the film Futurama: The Beast with a Billion Backs, Wernstrom mentions that Farnsworth is a recipient of the Fields Medal, which is awarded only to mathematicians under 40 years of age. He is also known to have created several doomsday devices, one of which was used to stop time skips.

^Verrone, Patric. "Futurama Writer/Co-Executive Producer Patric Verrone". theStream.tv. Retrieved 29 December 2011. Patric Verrone: Normally the voice of Professor Farnsworth, the leader of the Action Defense Team there, is played by Billy West. This was actually David Herman- who did the voice.